In present day nuclear steam generators of the shell and tube type, problems are encountered by solids that settle out of the secondary liquid. These solids generally settle out on the upper face of the tube sheet, with annual accumulations of several hundreds pounds, several inches in depth. This sludge, containing magnetite-copper compounds from the feed water heater, condenser, etc., may corrosively attack the inconel tubes of the steam generator, and over a period of years can cause many of the tubes to fail, requiring these tubes to be sleeved or plugged and effectively removed from service. Many steps have been taken to relieve this sludge build-up problem. Better materials have been used in the feed water heaters and condensers; flow distribution plates have been positioned above and close to the tube sheets to increase flow velocities; and sludge lancing of the formed sludge deposits with high pressure jets is done during scheduled outages to break and remove such deposits. Even with the above steps taken, sludge deposits on the upper surface of the tube sheet remain a problem.